DTC U1128: Loss Of Serial Communications - IRC: Description
When ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a State Of Health (SOH) message every 2 seconds to indicate system is operating properly. DTC U1128 will set when PZM does not receive SOH message from Integrated Radio Controller (IRC) after 3 consecutive monitoring cycles. DTC U1128 will clear when IRC transmits SOH message to PZM.